1. Field of the Invention
The present invention relates to a semiconductor device, and more particularly, to a method for solving the dishing problem that the dielectric layer in the peripheral region of the semiconductor device has a concave top surface during the planarization process, and improves the yield of the semiconductor device.
2. Description of the Prior Art
Dynamic random access memory (DRAM) is a major volatile memory and is an important element in many electronic products. DRAM consists of a large number of memory cells aggregated to form an array region for storing data. Each memory cell is composed of a metal oxide semiconductor (MOS) transistor connecting a capacitor.
The capacitor is located in a memory region, while a peripheral region is disposed adjacent to the memory region. The peripheral region includes other transistors and contact structures. In general, the capacitor located in the memory region has a higher height, thereby having better charge-storage efficiency. However, since the unbalance force or the difference of the capacitance height, the quality of the elements formed in the boundary between the memory region and the peripheral region may be influenced.